Fe 2 3 



H 2 0- 



H 2 + 



Na 2 



C0 2 



4-22 



1-46 

 [F = 



0-60 



1-55 

 : 0-31 = 



0-70 .... 



[100 

 1-31 0-9 

 : 99-93 less '13 



■u" 



0-43 



— 4 



C. Palache — Mineralogy of Franklin Furnace, N . J. 181 



tinctions between these pyroxenes are not sharply defined. 

 Jeffersonite, the most abundant of them, contains manganese 

 zinc and iron in addition to lime and very little magnesium. 

 Zinc schefferite differs in the practical absence of iron and in 

 the increase of calcium and magnesium at expense of man- 

 ganese and zinc. Schefferite, close to the last named, contains 

 no zinc, little iron and a larger proportion of magnesium. 

 Schefferite was found only in well-defined crystals in lime- 

 stone from Stirling Hill. The analyses here given are of a 

 very fresh jeffersonite from Parker shaft, Franklin Furnace, 

 and of schefferite which has not been before described from 

 this region. 



1. Analysis of jeffersonite, Steiger, U. S. G. S., 1906. 



2. Analysis of schefferite, Schaller, IT. S. G. S., 1907. 



Si0 2 CaO MgO MnO ZnO FeO A1 2 3 



1 49-03 19-88 5-81 7-91 7-14 3-95 0'86 



2 49-80 21-07 12-35 9'69 tr. 1-61 0'26 



Nasonite : Crystal Form. 



The crystal form of nasonite could not be determined by 

 Penfield in the absence of crystals, but he concluded that it 

 was tetragonal because of chemical analogy with ganomalite — 

 a tetragonal mineral. 



Crystals of nasonite were intrusted to the writer by Mr. 

 Canfield, who had recognized their hexagonal character. One 

 of them proved_ measurable and showed the forms a (1120), 

 m (1010), p (1011) and x (9092), the hexagonal symmetry 

 being well defined. The axial ratio, based on two measure- 

 ments of angle c a p = 56° 40', is a:c=l : 1-3167. 



Angle c /\ x, calculated 81° 41', measured 81° 36 r . 



The faces of m are cavernous except at the prism edges, 

 where they are well defined and generally truncated by a. 

 The prism rounds over into the pyramid p on most of the small 

 crystals seen, the form x representing a plane face t in this 

 surface on one crystal. The faces of p were dull on all except 

 the measured crystal. This was afterwards tested qualitatively 

 and gave the reactions of nasonite. 



Glaucochroite : Crystal Form. 



Terminated crystals were not present in the original speci- 

 mens of glaucochroite described by Penfield, but he obtained 

 an approximate axial ratio by measurement of the inclination 

 of individuals in twin position. 



Two terminated crystals were secured from a specimen 

 loaned by the Foote Mineral Co. which yielded fair measure- 

 ments, determining the following axial ratio and forms. 



